1. Field of the Invention
The present invention relates to components for use in a modular prosthetic limb wherein the effective length of the limb is adjustable to suit the particular needs of a person as the person grows and/or shrinks due to age or any other reason.
2. Description of the Related Art
Sometimes, due to accidents, health problems, birth defects, etc., people 5 need to have a limb 6 amputated. The amputated limb 6 terminates in a stump 7. In general, a socket 10 can be formed for any particular stump 7. Those sockets 10 are well known in the art, and each socket 10 has a central axis 11 and an end 12.
Fortunately for people requiring a prosthetic limb, much advancement has been made in the field of prosthetic limbs. People now have many choices, including endoskeletal and exoskeletal prosthetic limbs. The present invention relates generally to endoskeletal prosthetic limbs. That is, limbs comprised of structural components and that may have an optional aesthetic outer shell.
One conventional and exemplary prosthetic limb setup is shown in FIG. 1. As shown, a conventional socket 10 is shown connected to a stump 7. The socket 10 has a socket central axis 11 and has an end 12. A three prong adapter 30 has a central axis and is shown to be connected to the socket 10. The three prong adapter 30 is capable of being connected to the socket 10 at a rotational angle relative to the three prong adapter central axis. Hence, the three prong adapter 30 can be positioned in any rotational orientation relative to the socket 10 in the lateral direction 15, the medial direction 16, the anterior direction 17 and the posterior direction 18. A pyramidal adapter 130 is shown connected to the three prong adapter 30. A pylon 40 with a fixed receiver 41 is shown connected to the pyramidal adapter 130. A tube clamp 43 is shown connected to the pylon 40. The pylon 40 must be fully received within the tube clamp 43 in order to be properly connected thereto. The tube clamp 43 has a pyramidal receiver 44 that connects to a foot adapter 46. The foot adapter 46, in turn, connects to a prosthetic foot 49.
This and other existing prosthetic limbs generally work quite well for their intended purposes. Yet, certain drawbacks and disadvantages can be associated with existing prosthetic limbs.
As a general matter, great skill is required to construct and assemble a prosthetic limb. As shown in FIG. 1, a prosthetic limb may involve several components. Yet, the components shown only comprise one set up. Many other components exist. The practitioner first has to select desired components from a multitude of component options. Next, the practitioner needs to determine the overall length and orientation of the prosthetic limb. This step involves selecting and sizing the components so that the prosthetic limb will have a length that is identical to that of the natural limb. Additionally, the practitioner will need to account for any angular and rotational adjustments that may be necessary to properly fit the prosthetic limb to the person.
Frequently, the practitioner decides to incorporate a pylon into the prosthetic limb. The practitioner can easily cut the pylon to a predetermined length using conventional methods. The cut end of the pylon can be connected to and secured in place with the clamp of an adjacent component. To accomplish this, the pylon must be fully received within the tube clamp and there is no ability to longitudinally adjust the pylon with respect to the tube clamp. One apparent drawback is that the pylon must be cut to an exact length in order for the overall length of the prosthetic limb to be correct. Yet, sometimes the practitioner miscalculates the amount of the pylon that needs to be cut off. In this case, the overall length of the prosthetic limb would be too long or too short. In the event that the overall prosthetic limb is too long, more of the pylon can be cut off to remedy the problem. Yet, if the pylon is cut too short, a new pylon will need to be cut in order to remedy the situation. Hence, the process of properly sizing the pylon can be both time consuming and wasteful.
A further drawback, given that the pylon is not longitudinally adjustable with respect to the tube clamp, is that there exists an inability to finely tune a conventional prosthetic limb. That is, if the practitioner miscalculates or misconstructs the prosthetic limb even by a fraction of an inch, there is no way to overcome the shortcomings in the prosthetic limb simply by making an adjustment between the pylon and the tube clamp. In this event, absent construction of new components, the person may be forced to live with an improperly fitting prosthetic limb.
A further drawback is evident upon comparison of FIGS. 2 and 3. In FIG. 2, the person 5 is properly fitted with a prosthetic limb. Yet, the duration of time during which the prosthetic limb will properly fit is necessarily limited. Existing prosthetic limbs may initially fit well but may not fit well after the person grows or shrinks. FIG. 3 shows such a situation. In FIG. 3, the person has grown and the prosthetic limb has become too short. Specifically, the prosthetic limb is shorter than the natural limb by an offset length OL. While not specifically shown, it is noted that the opposite is true when a person shrinks. In such a case, the initially properly sized prosthetic limb will become too long. These problems are most prevalent in the young and the elderly, respectively. Given the inability to adjust the effective length of the prosthetic limb, the practitioner will need to replace major components of the limb or even construct an entirely new prosthetic limb as the size of the person changes. Replacing major prosthetic componentry is expensive, both in materials and in the practitioner's time, and is also inconvenient.
The time, cost and inconvenience associated with replacements and adjustments of conventional prosthetic limbs may have the effect of encouraging infrequent visits to the practitioner. As the duration of time between visits increases, the prosthetic limb continues to fit worse and worse. In turn, the person may become dissatisfied with their prosthetic limb.
Thus there exists a need for modular prosthetic limb components that solve these and other problems.